Sterilization chambers are used to sterilize product, such as medical devices, on a very large scale. Such chambers are typically controlled by a Programmable Logic Controller (PLC).
A sterilization cycle is defined by a sequence of phases to be performed by the chamber. For example, phases may involve operations like injecting or removing gases like steam, nitrogen, Ethylene Oxide (EtO), or air from the chamber, at specific pressures, rates, temperatures, and for specific time periods. These operations are performed by devices of the chamber, such as a valve, or a pump, and feedback from the chamber environment is obtained through sensors such as temperature or pressure sensors. Different devices and sensors may be attached to each chamber and each such hardware configuration may be controlled and monitored using a specific version of control software.
To ensure proper sterilization of the product, the sterilization cycles have to be performed consistently with a high degree of confidence. However, when an operator has chambers from different manufacturers, having a variety of sizes and hardware configurations, it becomes more and more difficult to ensure quality control across all chambers.
Over time, features may be added or removed, creating further software versions that need to be maintained for every type of chamber.
Furthermore, with each chamber running its own custom program, debugging becomes much more difficult and labor intensive. Each chamber program needs to be maintained separately, and a software upgrade on one chamber may affect other chambers differently, require testing for every chamber.
Since the PLC control program for each chamber typically combines configuration data, state chamber information, and program code in the same memory area, new program code may not be downloaded without overwriting and consequently losing configuration data and state chamber information. This applies especially if the memory structure, of the new software version, is different from the old version. This is typically overcome by having a developer implement each program code update in each chamber PLC manually.
The present disclosure provides methods and apparatus to overcome these and other deficiencies.